The purpose of this collaborative project of Tufts-New England Medical Center and the C.S. Draper Laboratories is to design, construct and test a stand-alone metaphase finding microscope incorporating a minicomputer. It is to be built modularly, largely from commercially available components which do not need continuous maintenance by staff experts in optics and electronics, and its construction is to be thoroughly documented. The components include a Zeiss Universal Microscope with automatic camera, a large 10 micron per step Zeiss Stepping Stage, a Data General Nova 3 computer and a Fairchild 1024 element self-scanning (CCD) linear array sensing device. The preprocessor for high speed (5 minutes per slide for about 100 metaphases) operation, the special high resolution high speed fractional stepping motor drive electronics and the software to operate the system are the major components not commercially available which we are building. This philosophy will permit cytogenetics laboratories to assemble copies of this system at minimal cost. A proposed independent evaluation of 2 copies of the finished instrument by several cytogenetics laboratories, which had been proposed as a third year effort, was not approved when this grant was awarded with considerable budget and time cuts. As such an evaluation and possible modifications resulting therefrom may be necessary to ensure acceptance by the cytogenetics community, we plan to request a renewal as soon as preliminary tests show the success of the proposed system. BIBLIOGRAPHIC REFERENCES: Necheles, T.F., J.F. Brenner, I. Bonacossa, R. Fristensky and P.W. Neurath: The Computer-Assisted Morphological Classification of Acute Leukemia I. Preliminary Results. Biomedicine 25:241, 1976. Brenner, J.F., B.S. Dew, J.B. Horton, T. King, P.W. Neurath and W.D. Selles: An Automated Microscope for Cytologic Research: A Preliminary Evaluation. The Journal of Histochemistry and Cytochemistry 24:100 1976.